System comprising bacteriophages and particles that contain active substances

ABSTRACT

The present invention concerns a system, comprising bacteriophages and particles comprising active agents, in which a first additional peptide is fused to proteins of the bacteriophage, the first additional peptide adheres to the surface of the particle and furthermore a second additional peptide is fused to proteins of the bacteriophage. The second additional peptide can adhere on substrate surfaces. The present invention furthermore concerns the use of the system for delayed release of active agents and also a method for production of the system. The present invention furthermore concerns a method for the selection of phage species from a combinatorial phage population.

This application is a division of U.S. patent application Ser. No.12/672,096, now allowed, which is a 371 of International PatentApplication No. PCT/EP08/06336, filed Aug. 1, 2008, which claimspriority of German Patent Application No. 10 2007 036 866.8, filed Aug.6, 2007, the entire disclosures of which patent applications areincorporated herein by reference.

The present invention concerns a system comprising bacteriophages andparticles including active agents. These particles containing activeagents are either pure active agent particles or capsules that containat least one active agent and are hereinafter called “particles” forshort. The present invention furthermore concerns the use of the systemfor the delayed release of active agents and a method for production ofthe system. The present invention furthermore concerns a method forselection of phage species from a combinatory phage population.

Known methods for bonding of active agents are for example impregnation,covalent binding of the active agent to the surface of a substrate orintegration of the active agent in a material and delaying the releaseof the active agent by means of additives or by integration ofprolonged-release formulations such as capsules in the material. Areview concerning the bonding of active agents to substrates can befound for example in Kaldsz and Antal, Current Medicinal Chemistry,2006, 13, 2535-2563.

Depending on the substrate, the impregnation methods require anintensive and repeated treatment of the substrate, with a higher risk ofside effects. Active agents or mixtures of active agents can be washedout by environmental effects or washes if the adherence is inadequate.Depending on the substrate, a covalent chemical bond or integration ofparticles may moreover be difficult to achieve (hairs, skin) ordangerous to health (textiles).

The combination of an inorganic substrate with biological components forthe modification of surface properties is known in biomimetics.Bacteriophages presenting short peptides, selected from a phage library,have for example hitherto been used to precipitate or cut off inorganicmaterials (WO2003/078451). Hybrid materials consisting of an inorganicsubstrate and specific polypeptide ligands are used as a potentialsolution for modification of the substrate surface. The identificationof the suitable biological ligand for the substrate (usually a peptide)is time-consuming and expensive, however, and has hitherto been anobstacle to a concrete application. The concept of a bifunctional ligandfor binding two inorganic components is referred to in the prior art(see for example Sarikaya et al., Nature Materials, 2003, 2, 577-585).The binding of cells or biomolecules to a polymer substrate, inparticular to oxidized chlorine-enriched polypyrrol (PPyCl) orpoly(lactate-co-glycolate) (PLGA), by bacteriophages with bifunctionalbinding properties, has been specifically described for example inWO2004/035612. WO2004/035612 mentions the theoretical possibility ofbinding drugs by this method to the substrate, but only describes theidentification of the polymer-specific phage by so-called biopanning andbinding of the phage to the polymer substrate. The further binding to afurther substance which is not a biological binding partner of the phageused, such as a drug for example, is not further described, althoughthis binding would also have to be selective and would require precisematching of the ligand to the other binding component.

The problem was therefore to provide a system comprising bacteriophagesand particles including active agents, in which the phage adheres to theparticle and is furthermore suitable for adherence to a substratesurface.

The solution to this problem according to the invention was that a firstadditional peptide is fused on proteins of the bacteriophage, the firstadditional peptide adheres to the surface of the particle andfurthermore a second additional peptide is fused on proteins of thebacteriophage.

Active agents are first of all substances or mixtures of substances thathave an effect desired by the user on an organism, irrespective ofwhether the latter is of a human, herbal or other nature. In thelinguistic usage of the present invention, proteins of the bacteriophagemeans gene products of the phage genome which for example build up theshell of the bacteriophage. A first additional peptide is a peptidewhich is not contained on the natural foul' of the phage, but is forexample presented by means of molecular-genetic manipulations of thephage genome on the phage. The peptide is fused to proteins of thebacteriophage, which means that is linked either N-terminally orC-terminally to the protein via a peptide bond.

Particles comprising active agents within the meaning of the presentinvention are in particular microparticles that exhibit a particlediameter with a d90 value of the volume-weighted distribution ≧0.1 to≦300, preferably ≧0.3 to ≦100, especially preferably ≧0.5 to ≦30micrometers. Particles with such sizes are firstly well-suited foradherence to bacteriophages according to the invention. Secondly,particles of such sizes are advantageous with the procedures describedabove for the production of microparticles. The d90 value of thevolume-weighted distribution is that particle size for which it is truethat 90% of the particle volume is formed by particles smaller than orequal to the d90 value. Measurement methods for determination of thevolume-weighted distribution are listed for example in Terence AllenParticle Size Measurement, Kluwer Academic Publishers,Dordrecht/Boston/London 1999, p. 404 et seq. The representation of theresults is also indicated in this bibliographic reference or can alsotake place in accordance with the standard DIN ISO 9276-1.

The first additional peptide has the property of adhering to the surfaceof the particle. The particle and bacteriophage are consequentlyconnected to each other via the first peptide. The type of bond can forexample be a covalent bond, an electrostatic interaction via charged orpartially charged functional groups, or a hydrogen bridge bond. If anactive agent is encapsulated, one of the components of the capsule bindsto the phage. If the active agent occurs as a pure particle of activeagent, the phage binds directly to the pure active agent. Both forms ofbinding are brought together in the present invention under the term“particle”.

The second additional peptide is also a peptide which is not containedon the natural form of the phage, but is for example presented by meansof molecular-genetic manipulations of the phage genome on the phage. Thepeptide is fused to proteins of the bacteriophage, which means that itis linked either N-terminally or C-terminally to the protein via apeptide bond. This peptide is intended to make it possible for the phageand thus also the particle comprising active agents to adhere to asubstrate surface. The type of bond can for example be a covalent bond,an electrostatic interaction via charged or partially charged functionalgroups, or a hydrogen bridge bond.

In one embodiment of the present invention the first and/or the secondadditional peptide exhibit a length of ≧4 amino acids to ≦100 aminoacids, preferably ≧5 amino acids to ≦50 amino acids, more preferably ≧6amino acids to ≦20 amino acids. The peptides can be linear but alsolooped in structure. Peptides with such a number of amino acids can bereadily fused to the phage proteins by means of currentmolecular-biological methods and are suitable for adhering to surfaces.Examples of such peptides are linear peptides with a length of 7 aminoacids, linear peptides with a length of 12 amino acids or loopedpeptides with a length of 7 amino acids, which are linked by adisulphide bridge between two cysteine residues.

In a further embodiment of the present invention the amino acid sequenceof the second additional peptide was determined by panning of acombinatorial phage population on a substrate surface. For the evolutiveselection of some phage species from a large combinatorial phagepopulation (“phage display library”) on a substrate, a phage displaylibrary is usually exposed to a substrate in a buffered aqueousenvironment, so that the binding of some phages can take place.Non-specifically binding and weakly binding phages are washed off usingan aqueous washing buffer. Phages which are still binding after thewashing, and which are thus specific, are then detached (eluted) usinganother aqueous buffer, subsequently called elution buffer. This entireprocedure is called “panning”. The eluted phages are propagated andexposed to the substrate once again in further panning rounds, until apopulation of phages that bind well accumulates. Examples of thistechnique can be found in Sarikaya et al., Nature Materials, 2003, 2,577-585; O'Neil and Hoess, Current Opinion in Structural Biology, 1995,5, 443-449; Smith and Scott, Methods in Enzymology 1993, 217, 228-257;Sambrook and Russell (Ed.), 2001, Molecular cloning: A laboratory manual(third edition), Cold Spring Harbor Press, pages 18.115 to 18.122. Theamino acid sequence itself, which is responsible for the binding, can bedetermined by means of genetic engineering or molecular biology methods.

In a further embodiment of the present invention the bacteriophages areof type M13. These phages can be readily changed and are easilyobtainable and easy to propagate in culture. They exhibit for examplethe proteins gpIII, gpV, gpVI, gpVII, gpVIII and gpIX as gene products.It is possible that the first additional peptide is fused to the proteingpIII or gpVIII and the second additional peptide is fused to theprotein gpIII or gpVIII. The lengthening of these proteins withadditional peptides, i.e. the fusing, can be readily executed on theseproteins. It is especially preferable if the protein gpIII is fusedN-terminally with a peptide of the sequence ISSKPTSQLTTP (SEQ ID NO: 8)and the protein gpVIII is fused N-terminally with a peptide of thesequence STTRLR (SEQ ID NO: 9).

In a further embodiment of the present invention the active agents areselected from the group comprising insecticides and/or fungicides,preferably imidacloprid, deltamethrin, pemethrin, clotrimazole,bifonazole, preventol and/or trifoxystrobin; and also dexpanthenol. Suchactive agents benefit especially from the possibility of binding them toa substrate surface.

In a further embodiment of the present invention the particlescomprising active agents are encapsulated active agents. In variousareas of application, for example in the application of agrochemicals orpharmaceutical active agents, it is desirable to achieve for the purposeof topical treatment a long-term adherence of active agents and ascontrolled release thereof as possible in for example human beings orplants. To this end microparticles which comprise a matrix or a core, ashell and one or more active agents are linked to the previouslydescribed genetically engineered bifunctional bacteriophages.

Particles containing active agents, in particular microparticles,comprise one or more active agents which can be formulated as matrix orcore-shell particles. Procedures such as spray-drying, disk spraying,polymerization (interfaces, in situ etc.), coazervation and extrusionwith subsequent milling are used to produce such microparticles. Furtherproduction procedures are described for example in “MicrocapsuleProcessing and Technology” (Asaji Kondo, ISBN 0824768574, 1979, 1 etseq.).

Examples of such active agents are insecticides such as imidacloprid,deltamethrin or pemethrin and fungicides such as clotrimazole,bifonazole, preventol and trifoxystrobin.

“Matrix” or “shell” for the purposes of the present invention means thesubstance or mixtures of substances surrounding the active agent. Thematrix or shell can comprise the following auxiliary substances inaddition to the active agent: binding agents, synthetic macromolecules,fillers, dispersing agents, preservatives, antioxidants, wetting agents,surfactants and/or softeners or plasticizers.

The matrix is of such a nature that the release of the active agent overtime is adapted to the particular function.

It is possible that the total weight of the matrix or shell, relative tothe total weight of the microparticle, is ≧1 wt % to ≦99.9 wt %,preferably ≧5 wt % to ≦90 wt %, more preferably ≧10 wt % to ≦80 wt %.Such matrix or shell percentages allow bacteriophages according to theinvention to adhere to the auxiliary substances and active agentsemployed.

The matrix can furthermore comprise binding agents, syntheticmacromolecules and/or fillers.

These have inter alia the function of holding the individual componentsof the microparticle together in a stable foul' and/or releasing theactive agent or mixtures of active agent in a controlled manner.

Examples of binding agents can be selected from the group comprisingcellulose derivatives, microcrystalline cellulose, sodiumcarboxymethylcellulose, methylcellulose, hydroxypropyl-cellulose,hydroxypropylmethylmethylcellulose, lactose, starch (wheat, maize,potato, rice starch), starch derivatives, sucrose, glucose, mannitol,sorbitol, dicalcium phosphate, tricalcium phosphate, bolus, zinc oxide,gelatine, maltodextrins, polysaccharides, oligosaccharides, stearicacid, calcium stearate, shellac, cellulose acetatephthalate and/orhydroxylmethylcellulose phthalate.

Examples of synthetic macromolecules can be selected from the groupcomprising copolymerisates of dimethylaminoethacrylic acid and neutralmethacrylic acid esters, acrylic and methacrylic acid estercopolymerisates with trimethylammonium methacrylate, polymerisates ofmethacrylic acid and methacrylic acid esters, acrylic acid ethylester-methacrylic acid methyl ester-copolymerisate, styrene,acrylnitrile copolymer, polystyrene, polycarbonate, polyester,polyether, polyamides, polyimides, polyureas, polyurethanes,polysulphides, polyvinylpyrrolidone, polyvinylpyrrolidone vinylacetateand/or polyvinyl alcohols.

Examples of fillers can be selected from the group comprising mineralssuch as clay minerals and/or colloidal silicic acid such as for examplekaolin, kaolinite, halloysite, montmorillonite, talcum, bentonite,vermiculite and/or allophane. Minerals furthermore comprise oxides,hydroxides, silicates, carbonates and sulphates of calcium, magnesium,aluminium and titanium.

The matrix can furthermore comprise other auxiliary substances that areselected from the group comprising anion-active surfactants,non-ionogenic surfactants and/or lipids with ester linkage.

Examples of anion-active surfactants can be selected from the groupcomprising soaps, salts of fatty acids, sodium palmitate, sodiumstearate, sodium oleate, sodium salts of fatty alcohol sulphates,sulphoccinates, alkyl naphthalene sulphonates, and/or alkyl sulphates.

Examples of non-ionogenic surfactants can be selected from the groupcomprising partial fatty acid esters of polyvalent alcohols, partialfatty acid esters of sorbitans, partial fatty acid esters ofpolyhydroxyethylene sorbitan, polyhydroxyethylene fatty alcohol ethers,polyhydroxyethylene fatty acid esters, ethylene oxide-propylene oxideblock copolymers, ethoxylated triglycerides and/or silicone surfactants.

Examples of lipids with ester linkage can be selected from the groupcomprising glycerides, oils, 10hydrated oils, semi-synthetic andsynthetic glycerides, solid and semi-solid waxes, liquid waxes and/orphosphatides.

These auxiliary substances (binding agents, synthetic macromolecules,fillers, dispersing agents, preservatives, antioxidants, wetting agents,surfactants and/or softeners or plasticizers) can support the adherenceof bacteriophages according to the invention to microparticles. Inaddition, the auxiliary substances can facilitate the dispersion of themicroparticles in liquids and control the release of the active agent ormixture of active agent.

In a further embodiment of the present invention the material of theshell of the active agent capsule is selected from the group comprisingcopolymerisates of dimethylaminoethacrylic acid and neutral methacrylicacid esters, acrylic and methacrylic acid ester copolymerisates withtrimethylammonium methacrylate, polymerisates of methacrylic acid andmethacrylic acid esters, acrylic acid ethyl ester-methacrylic acidmethyl ester-copolymerisate, styrene acrylnitrile copolymer,polystyrene, polycarbonate, polyester, polyether, polyamides,polyimides, polyureas, polyurethanes, polysulphides,polyvinylpyrrolidone, polyvinylpyrrolidone vinylacetate and/or polyvinylalcohols. These materials can support the adherence of thebacteriophages according to the invention and also favorably affect therelease of the active agents.

In a further embodiment of the present invention the system additionallycomprises a substrate surface, where furthermore the second additionalpeptide adheres to the substrate surface. In this way the overall stateis described that the bifunctional bacteriophage acts as an adhesionagent between a particle comprising active agents and a substratesurface. The material of the substrate surface is preferably selectedfrom the group comprising polycarbonate, polyester, keratin, hairs,mucous membrane, skin, horn, textiles, cotton, wool, chitin, plantsand/or semi-conductors. Such substrate surfaces meet importantpharmaceutical and technical applications.

A further object of the present invention is the use of the systemaccording to the present invention for the fixing of active agents onsubstrates.

A further object of the present invention is the use of the systemaccording to the present invention for the delayed release of activeagents.

Underlying the present invention was the further problem of developing aprocedure for the selection of phage species from a combinatorial phagepopulation (panning procedure), in which in comparison to the prior artthe non-specifically binding and weakly binding phages in particular aremore effectively washed off a substrate with a rough surface. Thepresent invention therefore furthermore concerns a method for theselection of phage species from a combinatorial phage population. Thiscomprises the following steps:

-   -   a. A phage display library is exposed to a substrate in a        buffered aqueous environment,    -   b. Washing of the substrate,    -   c. Detachment of the binding phages using an aqueous elution        buffer,        where the washing of the substrate takes place with energy input        by means of ultrasonics.

What is advantageous in this process is that the detachment of thephages by means of ultrasonics makes it possible to select and detectthe phages that bind especially well. In each wash fraction the presenceof phages is preferably determined qualitatively for example by means ofa plaque assay spot test. With the procedure according to the invention,phage pannings can be carried out inter alia on substrates such aspolycarbonate, polyester, keratin, hairs, mucous membrane, skin, horn,textiles, cotton, wool, chitin, plants and/or semi-conductors.

Commercially available M13 phage display libraries are advantageouslyemployed which have a randomized peptide as gpIII fusion protein, inparticular as a linear peptide with a length of 7 amino acids, as alinear peptide with a length of 12 amino acids, or as a looped peptidewith 7 amino acids, which are linked by a disulphide bridge between twocysteine residues. Also conceivable is a combinatorial phage displaylibrary created by specific genetic engineering, which has a randomizedpeptide as gpIII fusion protein that exhibits a different length than 7or 12 amino acids. Alternatively a combinatorial phage display librarywhich contains randomized peptides fused on the gpVIII protein of theM13 bacteriophage can be created by specific genetic engineering of thephage DNA.

The elution conditions are preferably also adapted to the substrate orparticle in question, in order to detach the phages that bind wellcompletely from the surface. The elution can be performed in a gentlemanner by addition of an aqueous elution buffer, in which intact phagesare obtained. To this end the following parameters can be optimized:

-   -   pH value of the elution buffer usually pH 2 to pH 11.5, where        the pH of the wash buffer is closer to pH 7 than the pH of the        elution buffer, and preferably at least two elution operations        are carried out with different elution buffers. At least one        acidic and at least one basic elution operation are preferably        carried out.    -   Nature and concentration of the elution buffer substance, such        as alkaline phosphates for example (usually in concentrations        from 0.005 to 1.5 mol/L), Tris-HCl (0.005 to 1.5 mol/L), glycine        HCl (0.05 to 0.2 mol/L) or triethylamine (0.05 to 0.2 mol/L).    -   Presence, nature and concentration of salts, in particular        alkaline or alkaline earth halides, sulphates, carbonates,        phosphates or nitrates, preferably sodium chloride usually in        concentrations from 5 to 500 mmol/L, preferably 25 to 250        mmol/L, especially preferably 50 to 200 mmol/L.    -   Presence, nature and concentration of detergents, preferably        Tween®-20, sodium dodecyl sulphate (SDS), or Triton X-100,        usually in concentrations from 0.01 to 1 wt %, preferably        0.05-0.5 wt %.    -   Quantity of the elution buffer usually from 1 to 10 mL,        temperature of the elution buffer usually 4° C.-55° C.,        preferably from 15 to 40° C., duration of the elution preferably        at least 5 s,    -   Successive elutions can be carried out with the same or        different conditions, and the number of these elutions can be        adjusted (e.g. one elution with 0.1 mol/l glycine pH 2.0        followed by a neutralization step with 1 mol/l Tris-HCl pH 8,        followed by a second elution with 0.1 mol/l triethylamine pH        11.5 followed by a neutralization step with 1 mol/l Tris-HCl pH        7.5).

The method according to the invention for the above-mentioned adaptationof the washing and elution conditions to the substrate or to theparticle results in well binding genetically engineered phages which canbe selected in a shorter time from a combinatorial phage library than inhitherto used panning procedures.

The eluted phages are propagated and once again exposed to the substrateor to the particle. If further panning rounds are carried out,preferably under more stringent washing conditions, one obtains apopulation of specifically binding phages which are characterized inthat they present a short peptide on their proteins that are responsiblefor the binding. The sequence of this peptide chain can be determined bysequencing the phage DNA. This DNA sequence can be used to modify otherphages by genetic engineering in such a way that they present bindablepeptides as fusion proteins. Especially preferably bifunctional phageswhich bind with one of the peptides specifically to the particle, andwith the other peptide specifically to the substrate, are produced inthis way.

The present invention furthermore concerns a method for production of asystem according to the present invention in which in a phage of typeM13, preselected by panning, with a first additional peptide alreadyfused to gpIII, which imparts binding properties to an active agentparticle, a second additional peptide is fused to the gpVIII protein ofthe same phage clone, with it being possible for the peptides fused togpIII and gpVIII to be the same or different.

Also conceivable is a method for production of a system according to thepresent invention in which in a phage of type M13, preselected bypanning, with a first additional peptide already fused to gpIII, asecond additional peptide which imparts binding properties to an activeagent particle is fused to the gpVIII protein of the same phage clone,with it being possible for the peptides fused to gpIII and gpVIII to bethe same or different.

One embodiment of the method comprises the following steps:

-   -   a. Restriction cleavage sites are introduced into the gpVIII        procoat sequence by performing localized mutagenesis on the        gpVIII procoat gene, which is located on a plasmid (preferably        pUC) between two suitable restriction cleavage sites (preferably        PagI and KpnI),    -   b. The mutations from step a) are transferred by recloning from        the plasmid into the replicative form (RF) of the M13 genome,        preferably in the form of the M13KE vector,    -   c. the replicative form of the phage DNA is cleaved with those        restriction enzymes whose cleavage sites were introduced by the        mutations from step a), and then serves to assimilate suitable        complementary oligonucleotides which at the ends show the        corresponding overhang for ligation into the open restriction        sites and which code for a second additional peptide sequence.

As a result of the panning and selection process there is preferablyalready a peptide fused to gpIII which imparts binding properties. Inorder to achieve bifunctionality, a further peptide which also imparts abinding property is usually fused to the gpVIII protein of the samephage clone by molecular-biological manipulation of the phage genome,with it being possible for the peptides fused to gpIII and gpVIII to bethe same or different, so that multiple binding properties can beachieved. In order to achieve this fusion, restriction cleavage sitesare first introduced into the corresponding position of the phagegenome. For cloning purposes the mutations are first introduced onanother plasmid, preferably pUC, which contains the gpVIII procoat genebetween two suitable restriction cleavage sites (preferably PagI andKpnI). The introduction of the new restriction cleavage sites into thegpVIII procoat sequence is performed by means of localized mutagenesis(e.g. Sambrook and Russell (ed.), 2001, Molecular cloning: A laboratorymanual (third edition), Cold Spring Harbor Press, pages 8.42 to 8.45)using oligonucleotides with suitable sequences, such as:

Mutagenic oligonucleotides (SEQ ID NO: 1) Nco-A5′-CGGCGTTCCCATGGTGTCTTTCGCTGC-3′ (SEQ ID NO: 2) Nco-B5′-GCAGCGAAAGACACCATGGGAACGCCG-3′ (SEQ ID NO: 3) Pst-A5′-GCTGTCTTTCGCTGCAGAGGGTGACGATCCC-3′ (SEQ ID NO: 4) Pst-B5′-GGGATCGTCACCCTCTGCAGCGAAAGACAGC-3′

The restriction cleavage sites introduced can be selected from the groupcomprising: Aar I, Aat II, Acc I, Acu I, Afl II, Age I, Ahd I, Apa I,ApaL I, Asc I, AsiS I, Avr II, BamH I, Bbs I, Beg I, BciV I, Bel I, BfrBI, Blp I, BmgB I, Bmt I, Bsa I, Bsg I, BsiW I, BspE I, BssH II, BssS I,BstAP I, BstB I, BstE II, BstX I, BstZ17 I, CspC I, EcoN I, EcoR V, FseI, FspA I, Hinc II, Hpa I, I-Ceu I, I-Sce I, Mfe I, Mlu I, Nco I, Nhe I,Not I, Nru I, Nsi I, PI-Psp I, PI-Sce I, PaeR7 I, PflF I, PflM I, Pme I,Pml I, PshA I, PspOM I, Pst I, Rsr II, Sac I, Sac II, Sal I, SanD I, SapI, Sca I, SexA I, Sfi I, SgrA I, Sma I, Spe I, Srf I, Stu I, Sty I, TliI, Tth111 I, Xba I, Xcm I, Xho I, Xma I, Zra I. An NcoI cleavage site ispreferably inserted in the signal sequence of gpVIII and a PstI cleavagesite in the mature region. These mutations are then transferred byrecloning from the plasmid into the replicative form (RF) of the M13genome, preferably in the form of the M13KE vector (New EnglandBiolabs). For this purpose the vector is cleaved with suitablerestriction enzymes, preferably PagI and KpnI, and the fragment obtainedis ligated into the similarly cleaved M13KE vector. For carrying outrestriction and ligation steps on double-stranded plasmids see forexample Sambrook and Russell (Ed.), 2001, Molecular cloning: Alaboratory manual (third edition), Cold Spring Harbor Press, pages 1.84to 1.87. For carrying out transformations of plasmids in E. colibacteria see Sambrook and Russell (Ed.), 2001, Molecular cloning: Alaboratory manual (third edition), Cold Spring Harbor Press, pages1.105-1.122.

After introduction of the cleavage sites into the M13 genome, thereplicative form of the phage DNA can usually be cleaved with the tworestriction enzymes NcoI and PstI and then serves to assimilate suitablecomplementary oligonucleotides which at the ends show the correspondingoverhang for ligation into the open restriction sites and which code fora peptide sequence conferring adherence. The information for thispeptide sequence conferring adherence can originate from the panningprocedure of the gpIII phage display library on a suitable substrate. Byligation of the DNA and transformation into suitable host bacteria,bifunctional phages which if necessary present different peptidesequences conferring adherence both on their gpIII and on their gpVIIIproteins can be produced.

Alternatively, instead of oligonucleotides which code for a peptidesequence conferring adherence, library oligonucleotides can also beligated into the suitably cleaved M13 genome. These are usually twocomplementary oligonucleotides which at the ends show the correspondingoverhang for ligation to the open restriction sites. In addition theyhave a range of usually 15 bases that are freely variable. By ligationof the hybridized oligonucleotides into the cleaved RF DNA andtransformation into suitable host bacteria one obtains a randomizedgpVIII phage library. The phages can be selected by the alreadydescribed panning procedures on substrate surfaces.

The present invention furthermore concerns the use of a peptide of thesequence ISSKPTSQLTTspacer-PSTTRLR (SEQ ID NOS: 10-18) to conferadherence, where the spacer comprises ≧0 to ≦10 repeat units of theamino acids glycine and/or alanine. In the simplest case the spacer,i.e. the spacer between the specified peptide sequences, is not present.The spacer can, however, also comprise ≦10 or ≦5 repeat units of theamino acids glycine and/or alanine. Where both glycine and alanine arepresent, they can be arranged in any desired order. The specifiedsequences ISSKPTSQLTT (SEQ ID NO: 19) and PSTTRLR (SEQ ID NO: 20)correspond to the individual peptides determined in Example 6 below. Apeptide is in particular suitable for conferring adherence between apolycarbonate surface and a polyurethane surface.

The present invention is further illustrated below by means of Examples1 to 6.

EXAMPLES Example 1 Panning of a Combinatorial Phage Display Library (PhD12™ New England Biolabs) on a Polyurethane Substrate

Polyurethane substrate was produced from a mixture of equivalentquantities of Desmophen® 670 BA and Desmodur® N3300 (BayerMaterialScience AG), and hardened over 16 h at ambient temperature. 20mg of the substrate was equilibrated for 10 min in Tris-Buffered Saline(TBS, consisting of 50 mmol/l Tris-HCl pH 7.5, 150 mmol/l NaCl) andincubated for 60 min with 4*10¹⁰ pfu (10 μl of the original library) in1 ml TBS at ambient temperature. The substrate was washed ten times with10 ml TBST (TBS plus 0.1 vol.-% Tween-20) in each case (by means ofbrief vortexing, five minutes' rotation plus 5 s ultrasonic bath). Thefirst elution took place under acidic conditions by immersion of thesubstrate in 1 ml of 0.1 mol/l glycine pH 2.5 for 10 s with subsequentneutralization of the substrate in 1 ml of 0.1 mol/l Tris-HCl pH 8 for 1min. The first elution solution was neutralized by addition of 200 p. 1of 1 mol/l Tris-HCl pH 8. The second elution took place under basicconditions by immersion of the substrate in 1 ml of 0.1 mol/ltriethylamine pH 11.5 for 1 min with subsequent neutralization of thesubstrate in 1 ml of 0.1 mol/l Tris HCl pH 7.5 for 1 min. The secondelution solution was neutralized by addition of 200 p. 1 of 1 mol/lTris-HCl pH 7.5. The substrate was then preserved in TBST, in order toobserve time-dependent detachment effects of non-eluted phages.

In each fraction the presence of phages could now be determinedqualitatively by means of a plaque assay spot test (see FIG. 1). To thisend bacteria of the strain E. coli ER2738 (New England Biolabs) werestreaked on an LB Tet agar plate (15 g/l agar, 10 g/l Bacto-Trypton, 5g/l yeast extract, 5 g/l NaCl, 20 mg/l tetracycline) and incubated overnight at 37° C. 10 ml of LB Tet medium (10 g/l Bacto-Tryptone, 5 g/lyeast extract, 5 g/l NaCl, 20 mg/l tetracycline) was inoculated with anindividual colony ER2738 and shaken to an OD₆₀₀ of 0.4 at 37° C. 400 μlof it was pipetted in 3 ml of molten LB Agar Top (7 g/l agar, 10 g/lBacto-Tryptone, 5 g/l yeast extract, 5 g/l NaCl) and plated out on anLB-IPTG/X-gal plate (15 g/l agar, 10 g/l Bacto-Tryptone, 5 g/l yeastextract, 5 g/l NaCl, 1.25 mg/l isopropyl-13-D-thiogalactopyranoside, 1mg/15-brom-4-chlor-3-indoxyl-(3-D-galactopyranoside). After hardening, 3μl of each fraction was dripped onto the plate and this was incubatedover night at 37° C. The presence of phages in each fraction wasindicated by blue plaques.

The elution fractions (elution 1 and 2 and the two neutralizationsolutions) were combined and amplified. To this end 10 ml of LB Tetmedium was inoculated with 100 μl of an overnight culture ER2738 (in LBTet) and also the combined elution fractions and shaken for 4.5 h at 37°C. The culture was centrifuged for 10 min at 4500×g and 4° C., and thesupernatant was then centrifuged again. The top 4/5 vol. of thesupernatant was mixed with 1/5 vol. PEG/NaCl (20% (w/v) polyethyleneglycol 8000, 2.5 mol/l NaCl) and incubated for 1 h at 4° C. The phageswere centrifuged off for 20 min at 16000×g and 4° C. and resuspended in1 ml of TBS (50 mM Tris-HCl pH 7.5, 150 mM NaCl). The solution iscentrifuged for 5 min at 10000×g and 4° C., the supernatant is mixedwith 200 μl of PEG/NaCl and incubated for 60 min on ice. The phages werecentrifuged off for 10 min at 14000×g and 4° C. and resuspended in 200μl of TBS.

The titer of the phage solution was determined by a plaque assay. Tothis end 10 ml of LB-Tet medium was inoculated with an individual colonyER2738 and shaken to an OD₆₀₀ of 0.4 at 37° C. 400 p. 1 of it ispipetted into 3 ml of molten LB Agar Top, mixed with 10 μl of a suitabledilution of the phage solution and distributed on an LB-IPTG/X-galplate. After hardening, the plate was incubated over night at 37° C. Thetiter of the phage solution (in pfu/ml) could be calculated from thenumber of blue plaques.

In the following rounds the entire panning procedure was repeated, but1-2×10¹¹ pfu of the amplified eluate is used as a new library, inaddition the Tween 20 concentration is raised to 0.5% (v/v).

Three panning rounds in all were carried out. Specificallypolyurethane-binding phage clones whose identity could be determined bysequencing the variable range of their genome accumulated in theresultant population. To this end individual phage clones, e.g. from theLB-IPTG/X-gal 20 plate of the titration of the eluate of the thirdround, were retrieved with an inoculation loop and amplified separately:2 ml of LB-Tet medium was inoculated with 100 μl of an overnight cultureER2738 (in LB-Tet) and also the phage clone and shaken for 4.5 h at 37°C. The culture was centrifuged for 10 min at 4500×g and 4° C., and thesupernatant was then centrifuged again. 1 ml of the phage solution wasmixed with 500 μl of PEG/NaCl-Lsg and incubated for 2 h at 4° C. Thephages were centrifuged off for 15 min at 14000×g and 4° C. andresuspended in 100 p. 1 of 10 mM Tris-HCl pH 8.0, 1 mM EDTA, 4 M Nal.The DNA was precipitated by 250 μl of ethanol for 10 min and centrifugedoff for 15 min at 14000×g and 20° C. The pellet was washed with 70%ethanol, centrifuged for 1 min at 14000×g and 20° C., dried andresuspended in 30 μl of 10 mM Tris-HCl pH 8.0. The sequencing of the DNAwas performed with the primer 5′-CCCTCATAGTTAGCGTAACG-3′ (SEQ ID NO:21), with the anticodon strand of the M13 DNA being obtained.

Example 2 Unsuccessful panning of a combinatorial phage display library(Ph.D.12™, New England Biolabs) on a Polyurethane Substrate (withoutEnergy Input During the Washing)

The procedure is carried out in a similar way to the 1st round ofExample 1, except that there was no simultaneous energy input during thewashing steps. The fractions obtained were also checked by means of aplaque assay spot test qualitatively for the presence of phages (seeFIG. 2).

Example 3 Production Of a Combinatorial gpVIII Phage Display Library

To introduce an oligonucleotide bank for the Gene VIII (main shellprotein) into the M13 genome, three primers are needed:

1. Library oligonucleotide (SEQ ID NO: 5)5′CGTCACCCTCTGCAGC(NNN)₆AGCAGCGAAAGACACCATG GGAAGC 2. Extension primer I(SEQ ID NO: 6) 5′ CGTTCCCATGGTGTCTTTC 3. Extension primer II(SEQ ID NO: 7) 5′ ATCGTCACCCTCTGCA

A PCR reaction that is used to create the library is first performed onthe library oligonucleotide with both extension primers. The library isthen digested with NcoI and PstI and inserted into the correspondingrestriction sites in a M13KE vector having NcoI and PstI cleavage sites.

So as to be able to introduce the library into the M13 genome,restriction cleavage sites are first introduced into the correspondingposition of the genome of M13KE. For cloning purposes the mutations arefirst introduced on another plasmid (pUC) which contains the gpVIIIprocoat gene between the restriction cleavage sites PagI and KpnI(pUC-gp8). The introduction of the new restriction cleavage sites intothe gpVIII procoat sequence is effected by means of localizedmutagenesis (e.g. Sambrook and Russell (Ed.), 2001, Molecular cloning: Alaboratory manual (third edition), Cold Spring Harbor Press, pages 8.42to 8.45) using the following oligonucleotides:

Mutagenic Oligonucleotides (SEQ ID NO: 1) Nco-A5′-CGGCGTTCCCATGGTGTCTTTCGCTGC-3′ (SEQ ID NO: 2) Nco-B5′-GCAGCGAAAGACACCATGGGAACGCCG-3′ (SEQ ID NO: 3) Pst-A5′-GCTGTCTTTCGCTGCAGAGGGTGACGATCCC-3′ (SEQ ID NO: 4) Pst-B5′-GGGATCGTCACCCTCTGCAGCGAAAGACAGC-3′

In this way an NcoI cleavage site is inserted in the signal sequence ofgpVIII and a PstI cleavage site in the mature region (pUC-gp8mut). Thesemutations are then transferred by recloning from pUC-gp8mut into thereplicative foam (RF) of the M13KE genome. For this purpose pUC-gp8mutis cleaved with PagI and KpnI and the fragment obtained is ligated intothe similarly cleaved M13KE vector. For carrying out restriction andligation steps on double-stranded plasmids see for example Sambrook andRussell (Ed.), 2001, Molecular cloning: A laboratory manual (thirdedition), Cold Spring Harbor Press, pages 1.84 to 1.87. For carrying outtransformations of plasmids in E. coli bacteria see Sambrook and Russell(Ed.), 2001, Molecular cloning: A laboratory manual (third edition),Cold Spring Harbor Press, pages 1.105-1.122.

After introduction of the cleavage sites into the genome of M13KE(M13KE-gp8mut), its RF DNA is cleaved with the two restriction enzymesNcoI and PstI and the similarly cleaved library oligonucleotide isligated into this vector.

Each ligation product is different in the 6 NNN positions and thereforecodes for different amino acids at these 6 positions. The ligationmixtures represent the combinatorial gpVIII library and can be useddirectly for panning on a substrate, in a similar way to a commercialgpIIl phage display library (see above).

Example 4 Production of Particles Containing Active Agent by Means ofSpray-Drying

In this example the method of spray-drying was used for the productionof matrix particles containing active agent on a micro-scale. Theproduction process for encapsulation of the insecticide deltamethrin ina water-insoluble polymer (polystyrene) as matrix is described below.

The dispersion to be sprayed was an 0/W emulsion, with the followingcomposition:

-   -   O phase: 74% dichloromethane, 18% polystyrene, 8% deltamethrin    -   W phase: 99% distilled water, 1% alkyl polyglucoside

The deltamethrin and polystyrene were first dissolved indichloromethane, before this O phase was emulsified into the W phaseconsisting of distilled water and alkyl polyglucoside (emulsifier) withthe aid of an Ultra Turrax of the type IKA T18 with level 5 for about 3min. The production of the microparticles from the 0/W emulsion waseffected with the aid of a B-290 spray-drier from the Btichi company. Tothis end the 0/W emulsion was pumped by means of a hose pump (2 g/min)to a binary nozzle (nozzle cap 1.5 mm) and sprayed there with anatomisation gas (nitrogen) 500 L/h. In the spray cylinder the dropletswere dried to solid particles with the aid of a drying gas (nitrogen,gas throughput about 31 m³/h), with the entry and exit temperature being100° C. and 54° C. The solid particles were then separated from thedrying gas in a cyclone. The microparticles so obtained consisted ofdeltamethrine, polystyrene, alkyl polyglucoside and a residual contentof solvent (<5 wt %). The particle size distribution of the particlescontaining active agent, determined by laser diffraction in an aqueousdispersion, showed a d90 value of the volume-weighted distribution of 28μm.

Example 5 Panning of a Combinatorial Phage Display Library on ParticlesContaining Active Agent

20 mg of the particles containing active agent from Example 4 wasequilibrated for 10 min in TBS and incubated for 60 min with 4*10¹⁰ pfuof the combinatorial gpVIII library from Example 3 in 1 ml of TBS atambient temperature. The particles containing active agent were washedten times with 10 ml of TBST (TBS plus 0.1 vol.-% Tween-20) in eachcase, being briefly vortexed and incubated for 5 min on a rotator and 5s in an ultrasonic bath. They were then centrifuged off for 1 min at14000×g, the supernatant was discarded and the pellet was gathered innew washing buffer with brief vortexing. The first elution took placeunder acidic conditions by incubation of the particles containing activeagent in 1 ml of 0.1 mol/l glycine pH 2.5 for 10 s with subsequentcentrifugation (1 min at 14000×g) and neutralization of the particlescontaining active agent in 1 ml of 0.1 mol/l Tris-HCl pH 8 for 1 min,followed by centrifugation again. The first elution solution wasneutralized by addition of 200 pi of 1 mol/l Tris-HCl pH 8. The secondelution took place under basic conditions by incubation of the particlescontaining active agent in 1 ml of 0.1 mol/l triethylamine pH 11.5 for 1min with subsequent centrifugation (1 min at 14000×g) and neutralizationof the particles containing active agent in 1 ml of 0.1 mol/l Tris-HClpH 7.5 for 1 min, followed by centrifugation again. The second elutionsolution was neutralized by addition of 200 p. 1 of 1 mol/l Tris-HCl pH7.5. The particles containing active agent were then preserved in TBST,in order to observe time-dependent detachment effects of non-elutedphages.

In each fraction the presence of phages could now be determinedqualitatively by means of a plaque assay spot test. To this end bacteriaof the strain E. coli ER2738 (New England Biolabs) were streaked on anLB Tet agar plate and incubated over night at 37° C. 10 ml of LB Tetmedium was inoculated with an individual colony ER2738 and shaken to anOD₆₀₀ of 0.4 at 37° C. 400 p. 1 of it was pipetted in 3 ml of molten LBAgar Top and plated out on an LB-IPTG/X-gal plate. After hardening, 3 p.1 of each fraction was dripped onto the plate and this was incubatedover night at 37° C. The presence of phages in each fraction wasindicated by blue plaques.

The elution fractions (elution 1 and 2 and the two neutralizationsolutions) were combined and amplified. To this end 10 ml of LB Tetmedium was inoculated with 100 μl of an overnight culture ER2738 (in LBTet) and also the combined elution fractions and shaken for 4.5 h at 37°C. The culture was centrifuged for 10 min at 4500×g and 4° C., and thesupernatant was then centrifuged again. The top 4/5 vol. of thesupernatant was mixed with 1/5 vol. PEG/NaCl and incubated for 1 h at 4°C. The phages were centrifuged off for 20 min at 16000×g and 4° C. andresuspended in 1 ml of TBS. The solution is centrifuged for 5 min at10000×g and 4° C., the supernatant is mixed with 200 μl of PEG/NaCl andincubated for 60 min on ice. The phages were centrifuged off for 10 minat 14000×g and 4° C. and resuspended in 200 μl of TBS.

The titer of the phage solution was determined by a plaque assay. Tothis end 10 ml of LB-Tet medium was inoculated with an individual colonyER2738 and shaken to an OD₆₀₀ of 0.4 at 37° C. 400 p. 1 of it ispipetted into 3 ml of molten LB Agar Top, mixed with 10 μl of a suitabledilution of the phage solution and distributed on an LB-IPTG/X-galplate. After hardening, the plate was incubated over night at 37° C. Thetiter of the phage solution (in pfu/ml) could be calculated from thenumber of blue plaques.

In the following rounds the entire panning procedure was repeated, but1-2×10¹¹ pfu of the amplified eluate was used as a new library, inaddition the Tween 20 concentration was raised to 0.5% (v/v).

Three panning rounds in all were carried out. Phage clones that bindspecifically to the particles containing active agent accumulated in theresultant population. Their identity could be determined by sequencingthe variable range of their genome. To this end individual phage clones,e.g. from the LB-IPTG/X-gal plate of the titration of the eluate of thethird round, were retrieved with an inoculation loop and amplifiedseparately: 2 ml of LB-Tet medium was inoculated with 100 μl of anovernight culture ER2738 (in LB-Tet) and also the phage clone and shakenfor 4.5 h at 37° C. The culture was centrifuged for 10 min at 4500×g and4° C., and the supernatant was then centrifuged again. 1 ml of the phagesolution was mixed with 500 μl of PEG/NaCl-Lsg and incubated for 2 h at4° C. The phages were centrifuged off for 15 min at 14000×g and 4° C.and resuspended in 100 p. 1 of 10 mM Tris-HCl pH 8.0, 1 mM EDTA, 4 MNal. The DNA was precipitated by 250 μl of ethanol for 10 min andcentrifuged off for 15 min at 14000×g and 20° C. The pellet was washedwith 70% ethanol, centrifuged for 1 min at 14000×g and 20° C., dried andresuspended in 30 μl of 10 mM Tris-HCl pH 8.0. The sequencing of the DNAwas performed with the primer 5′-CCCTCATAGTTAGCGTAACG-3′ (SEQ ID NO:21), with the anticodon strand of the M13 DNA being obtained.

Example 6 Production of a Bifunctional Bacteriophage that has a Peptide12 Amino Acids in Length, Fused to gpIII and Binding Specifically toPolyurethane, and Also a Peptide 6 Amino Acids in Length, Fused togpVIII and Binding Specifically to Polycarbonate

As a result of the panning of a commercial phage library (Ph.D.12™′ NewEngland Biolabs) on polycarbonate, a peptide 12 amino acids in length(ISSKPTSQLTTP (SEQ ID NO: 8)), fused to gpIII, and having polycarbonatebinding properties, was available in a phage clone (“PCO2-11”). In orderto achieve bifunctionality, a further peptide 6 amino acids in length(STTRLR (SEQ ID NO: 9)), having polyurethane binding properties, wasfused to the gpVIII protein of the same phage clone. The clone with thissequence (“PUR01-1”) was found by panning of a randomized gpVIII phagedisplay library (see above) on polyurethane.

In order to achieve the combination, the replicative form of PUR01-1 wasfirst cleaved with the restriction enzymes PagI and .KpnI. The insertthat contains the gpVIII gene with fused polyurethane-binding peptidewas ligated into the replicative form of PCO2-11, which was also cleavedwith PagI and KpnI. Bifunctional phages that present different peptidesequences conferring adherence on their gpIII and on their gpVIIIproteins were produced by transformation into competent E. coli ER2738bacteria (New England Biolabs).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Plaque assay of panning fractions (Round 1), dripped undilutedonto an LB-Agar-Top inoculated with E. coli ER2738 on an LB-IPTG/X-galplate. 0: library of Round 1 after the substrate incubation; W1-10: washfractions 1-10 (use of ultrasonics); E1: elution 1(acidic); N1:neutralization 1; E2: elution 2 (basic); N2: neutralization 2; TBST:preservation of the substrate piece after panning in TBST.

FIG. 2: Plaque assay of palming fractions (Round 1), dripped undilutedonto an LB-Agar-Top inoculated with E. coli ER2738 on an LB-IPTG/X-galplate.

0: library of Round 1 after the substrate incubation; W1-10: washfractions 1-10 (without use of ultrasonics); E1: elution 1 (acidic); N1:neutralization 1; E2: elution 2 (basic); N2:

neutralization 2; TBST: preservation of the substrate piece afterpanning in TBST.

1. Method for the selection of phage species from a combinatorial phagepopulation, comprising the following steps: a. exposing an A Phagedisplay library to a substrate in a buffered aqueous environment, b.washing the substrate, c. detaching the binding phages using an aqueouselution buffer, wherein the washing of the substrate takes place withenergy input by means of ultrasonics.
 2. Method for the production of asystem comprising a bacteriophage and a particle comprising an activeagent, wherein a first additional peptide is fused to a protein of thebacteriophage, the first additional peptide adheres to a surface of theparticle and furthermore a second additional peptide is fused to aprotein of the bacteriophage, said method comprising providing a phageclone of type M13, preselected by panning, with a first additionalpeptide already fused to gpIII, which imparts binding properties to anactive agent particle, and fusing a second additional peptide to thegpVIII protein of the same phage clone, with it being possible for thepeptides fused to gpIII and gpVIII to be the same or different. 3.Method according to claim 2, comprising the following steps: a.introducing restriction cleavage sites into the gpVIII procoat sequence,by carrying out localized mutagenesis on the gpVIII procoat gene, whichis located on a plasmid between two suitable restriction cleavage sites,b. transferring the mutations from step a) by recloning from the plasmidinto the replicative form (RF) of the M13 genome, c. cleaving thereplicative form of the phage DNA with those restriction enzymes whosecleavage sites were introduced by the mutations from step 1), and thenserves to assimilate suitable complementary oligonucleotides which atthe ends show the corresponding overhang for ligation into the openrestriction sites and which code for a second additional peptidesequence.
 4. Method according to claim 3, wherein the restrictioncleavage sites are an NcoI cleavage site in the signal sequence ofgpVIII and an PstI cleavage site in the mature region.
 5. Method for theproduction of a system comprising a bacteriophage and a particlecomprising an active agent, wherein a first additional peptide is fusedto a protein of the bacteriophage, the first additional peptide adheresto a surface of the particle and furthermore a second additional peptideis fused to a protein of the bacteriophage, said method comprisingproviding a phage clone of type M13, preselected by panning, with afirst additional peptide already fused to gpIII, and fusing a secondadditional peptide which imparts binding properties to an active agentparticle to the gpVIII protein of the same phage clone, with it beingpossible for the peptides fused to gpIII and gpVIII to be the same ordifferent.
 6. Method of conferring adherence, comprising conferringadherence with a peptide of the sequence ISSKPTSQLTT-spacer-PSTTRLR (SEQID NOS: 10-18), where the spacer comprises ≧0 to ≦10 repeating units ofthe amino acids glycine and/or alanine.